Every cardiologist has faced it: a patient with "moderate" secondary tricuspid regurgitation (STR) by ASE criteria where multiparametric assessment clashes with vena contracta or PISA, leaving with the second-guessing clinical decisions. The conventional 3-grade scheme (mild/moderate/severe) suffers from poor agreement between methods and wildly heterogeneous prognosis within the moderate group. 
Now, new research in 178 STR patients published in the Journal of the American Society of Echocardiography validates the expert-recommended 4-grade scheme, splitting moderate into mild-moderate and moderate-severe, and takes it further with a revised system using corrected PISA for superior accuracy.
Study Design: Head-to-Head Validation in Real STR Patients
Researchers enrolled 178 patients with secondary TR, applying both the ASE 3-grade scheme and expert 4-grade scheme (mild, mild-moderate, moderate-severe, severe). They quantified agreement using weighted kappa statistics between multiparametric integrated approach versus single-parameter methods. Right heart structure/function, including RV strain, right ventricular‒pulmonary artery (RV-PA) coupling, and conventional parameters, were compared across grades. The ROC analyses determined optimal cutoffs for effective regurgitant orifice area (EROA) and RegVol using the corrected proximal isovelocity surface area (PISA) method, refining the 4-grade system further.
4-Grade Scheme Crushes ASE: κ=0.901 vs κ=0.506
The results were dramatic. The expert 4-grade scheme achieved superb agreement between multiparametric RegVol assessment and single-parameter grading (κ = 0.901), obliterating the ASE 3-grade scheme's relatively low performance (κ = 0.506). Both schemes used the same quantitative backbone, but splitting the moderate group eliminated the prognostic heterogeneity plaguing ASE grading.
Right Heart Function Validates the New Hierarchy
The 4-grade stratification perfectly matched progressive right heart deterioration. RV strain and RV-PA coupling were significantly worse in moderate-severe STR versus mild-moderate STR (P < .05), confirming physiological plausibility. Conventional parameters showed expected gradients, but strain and coupling provided the most discriminant power between the split moderate grades—critical for timing interventions like transcatheter edge-to-edge repair or surgery.
Corrected PISA Cutoffs: New Echo Gold Standards
The study delivers game-changing quantitative thresholds via corrected PISA method. The study reported EROA 0.34 cm² (AUC = 0.945) and RegVol 35 mL (AUC = 0.958).
These values perfectly discriminate mild-moderate from moderate-severe STR, addressing PISA's known underestimation in TR. No more eyeballing borderline cases as these cutoffs provide black-and-white decision points.
Clinical Practice Transformed: From 3 Grades to Precision Medicine
This revised 4-grade scheme delivers superior multiparametric/single-parameter agreement, physiological validation via RV function, and precise cutoffs via corrected PISA. For STR patients, accurate grading isn't optional—it's outcome-determining.